1. Field of the Invention
The present invention relates generally to metal roof buildings having a central peak or ridge, and more particularly, to a vented closure system for venting hot air from the central peaks of such roofs while precluding wind-blown rain water from entering such roofs.
2. Description of the Relevant Art
Metal roofing has been used to cover buildings for many years. One common type of metal roofing is typically formed by ribbed steel deck panels supported upon purlins. An attic floor can be formed below the metal roof, in some cases; in other case, for example, farm buildings or warehouses, there may not be an enclosed attic separating the work space below from the metal roof.
When constructing metal roofs, the edges of adjacent metal roof deck panels are overlapped with each other to form a continuous sheet of roofing. Steel roof deck panels can easily be transported to a work site and are relatively simple to install. Metal roofs have a great number of advantages, including relatively high strength-to-weight ratios, long life, fire resistance, weather resistance (including resistance to hail damage), competitive material cost compared to other roofing options, and relatively low installation costs.
On the other hand, metal roofs, and metal buildings in general, tend to absorb heat from the sun during summer months. Reflective coatings, radiant barriers and/or insulation are sometimes added to such metal roof structures to improve energy-efficiency. Alternatively, for building spaces that are not air-conditioned, such as commercial warehouses, farm buildings, or enclosed attic spaces, it is known to form a ventilation gap along the ridge of the metal roof. The ventilation gap allows hot air, that would otherwise be trapped below the roof, to rise toward the ridge of the roof and escape to the exterior of the building. Of course, providing a vent along the ridge of the roof introduces another problem, namely, sealing the vent gap against the entry of rain and snow. In particular, buildings located in windy areas are often subject to wind-blown rain that, at times, is driven virtually horizontally along the roof.
Those skilled in the art have long attempted to solve the problem of effectively venting hot air from metal roof buildings through roof ridge vents while sealing out wind-blown moisture. For example, U.S. Pat. No. 5,022,203 to Boyd discloses a ridge vent structure for a metal roof. The roof structure includes wooden substrates below the steel roof panels, and further includes a pair of central wooden battens secured to such substrates along opposing sides of the ridge. The ridge vent includes a corrugated sheet secured to each of the wooden battens, a flat plate overlying each corrugated sheet, and a ridge cap extending thereabove. All of the aforementioned components are in addition to the metal roof panels that actually form the roof. Hot air escapes through gaps above and below each of the corrugated sheets.
U.S. Pat. No. 5,092,225 to Sells discloses a wooden roof structure that includes a vented ridge cap using a corrugated metal baffle member having holes formed therein for allowing hot air to escape from the roof through such holes.
U.S. Pat. No. 5,352,154 to Rotter, et al. discloses a metal roof ventilation system for placement along the ridge of the roof. Air permeable venting material is secured to the upper edges of metal roof panels by clips proximate to the peak of the roof, and ridge caps extend over the air permeable material and around the clips.
U.S. Pat. No. 5,704,834 to Sells describes a moisture resistant roof vent in which an air permeable, moisture repelling fabric covers the sides of the vent passages to try to prevent wind-driven rain from being blown into the ridge vent, and into the underlying building.
U.S. Pat. No. 5,921,863 to Sells discloses a wide variety of roof ventilating structures using a number of different baffles or louvers to form a vent path for hot air. The louvers are formed within essentially vertically-oriented members, causing the ridge cap to have a relatively tall profile.
U.S. Pat. No. 6,267,668 to Morris also discloses a ridge cap vent for metal roof systems. One or more corrugated layers are installed between the peak of the roof and the ridge cap, while closure strips are installed below each corrugated layer and the underlying metal roof panels. Hot air escapes through the paths formed along the corrugations of the corrugated layers.
Also, U.S. Pat. No. 7,594,363 to Polumbus discloses a ridge vent system for sloped metal roofs wherein an air-permeable sealing strip is secured to the roof panels near the ridge, and a ridge cap extends over the sealing strip.
While each of the aforementioned prior art roof ridge vents may offer benefits in particular applications, there is still a need for an efficient, inexpensive, and simple ridge roof vent for use with common metal panel roofs. For example, some of the roof vents shown in the prior art require specialized air-permeable membranes to resist the entry of moisture; apart from adding cost, such air-permeable membranes also restrict air flow to some extent. In addition, such air permeable membranes tend to shrink and deteriorate over time due to alternating cycles of heat and cold. After shrinking, such membranes often fall out of the ridge vent structure, allowing wind-blown rain to enter into the ridge vent.
Some of the vent structures described above require alteration of the normal procedures for installing metal roofs, as, for example, requiring support substrates or battens near the ridge of the roof. Still other roof vent structures shown in the prior art create air flow paths by spacing the side edges of the ridge cap above the upper plane of the metal roof panels, thereby complicating the attachment of the ridge cap to the underlying roof. Further, some of the prior art vent structures described in the patents referenced above require relatively tall baffles, thereby necessitating the use of higher profile ridge caps; in general, it is preferred to use ridge caps that do not form easily noticeable discontinuities in the roof line. In addition, apart from efficiently venting the roof of hot air and resisting entry of wind-blown rain, an ideal roof vent must also be relatively inexpensive, of simple construction, and easy to install.
Accordingly, it is an object of the present invention to provide a simple and inexpensive roof ridge vent to cover the ridge of a metal-roofed building while efficiently venting hot air from below the roof to the exterior.
It is a another object of the present invention to provide such a roof ridge vent that effectively resists moisture penetration, as from wind-blown rain.
It is still another object of the present invention to provide such a roof ridge vent that may readily be used with almost all conventional sloped metal roof decking panel designs.
It is a still further object of the present invention to provide such a roof ridge vent that does not require modification of techniques already used to construct metal roofs having a ventilation slot along the ridge of the roof.
Still another object of the present invention is to provide such a roof ridge vent that avoids the need for water-resistant membranes or fabrics that would otherwise lessen the rate of air flow.
Yet another object of the present invention is to provide such a roof ridge vent that permits the side edges of the ridge cap to be securely coupled to the underlying metal roof panels.
A still further object of the present invention is to provide such a roof ridge vent that allows for the use of a relatively low profile ridge cap to cover the vent along the ridge of the roof.
These and other objects of the invention will become more apparent to those skilled in the art as the description of the present invention proceeds.